Sizing.



' UNITED STATES PATENT OFFIC WILLIAM A. HALL, OF BELLOWS FALLS, VERMONT.

SlZlNG.

SPECIFICATION forming part of Letters Eatent No. 653,237, dated July 10, 1900.

Application filed May 13,1899. Serial No- 716,759. (No specimens.)

penetrate or permeate the same, which will.

not have a tendency to turn straw goods or paper containing ground wood yellow, and which will also have no tendency to discoloration of the goods when it is applied hot or when the goods are subjected to heat. To this end the new sizing consists of a chemical combination of casein, ammonia, and formaldehyde.

Many attempts have heretofore been made to produce a satisfactory sizing for paper, straw goods,&c., from casein; but such efforts have thus far been unsatisfactory. A patent was granted to George Vining January 13, 1880, No. 223,459, for a casein sizing for paper, &c., and which patent was subsequently purchased by me. The casein sizing made in accordance with i-he Vining patent could not be successfully used for the purpose intended,

principally because itwould not penetrate or permeate the goods, but would remain on the I surface, and also because it would turn straw goods and paper containing groundwood yellow. In the course of my experiments with casein sizing I discovered that if ammonia were used as a solvent the casein sizing would be caused to penetrate the goods; but this sizing still had the objection of 'discoloriug articles affected by alkali, and, moreover, paper or other goods sized with it were liable to be come very stick'y, even after having once been dried, if'the sized goods were exposed to moisture, asin a damp atmosphere. The tendency to stickiness with glue or gelatin sizing is readily overcome by the addition of a little alum 5 but no alum can'be used-in connection with casein-sizing without causing precipitation], and alum cannot, therefore, be used to correctthe tendency to stickiness with an am,-

moniacal casein sizing. To produce a casein sizing which would nothave a tendency to stickiness, I made attempts tonse formalde hyde instead of alum; but I found that the addition of formaldehyde to a solution of casein made with soda, potash, or borax caused aprecipitation, even when an amount of formaldehyde was used which was not fully sufiicient to overcome the alkalinity. Ifiuallydiscovered that formaldehyde acts entirely different it does on solutions of casein made with soda, potash, borax, or similar solvents. "Formaldehyde has a slight acid reaction, and enough of it can be added to an ammon-iacal solution of casein to neutralize the alkali, and even give the solutionsorne acidity, without any danger of precipitating or curdling, thus enabling the use of casein in sizing for paper or straw goods or other articles which would be affected by an alkali, as for such classes of on animoniacal solutions of -casein from whatgoods the sizing solution must be neutral or acid; An amm'oniacal solution of casein is of itself extremely unstable, turning dark Very rapidly when heated, and as it is necessary to use these solutions veryhot for some purposes, such ammoniacal solution is unfit for, most purposes for which a sizingis desired; but I havefound that the addition of formaldehyde completely overcomes this tendency of the so lution to turn dark when heated, and, more over, increases its penetrating or permeating effect. I V I My new casein sizing consists of about ninety parts of casein dissolved in about six parts of, preferably, a thirty-percent. solution of aminonia,- with the addition to the ammoniacal casein solution of about four parts of,preferably,a forty-per-cent. solution of for maldehyde-tl 1at is to say, enough ammonia,

. usually about six per cent. or seven per cent,

609,200, of August 8, 1898, but the combinaammonia and formaldehyde, insubstantially tion described in my said patent is used as a the proportions'specified. 1o Waterproofing agent and requires a mineral In testimony whereof I affix my signature retardent; but in the presence of two witnesses. ,i 5. WhatI doherein claim, and desire to secure 7 WILLIAM A. HALL.

by Letters Patent, isi Witnesses:

A sizing for paper, straw goods, &c., con- G.'M. SWEENEY,

sisting of a chemical combination of casein, 'T. H. RUSSELL. 

